They called Algar, who came the next day and spent just six minutes repairing the boiler before leaving.

Worried that the job wasn’t complete, the family called in another tradesman who found foil had been used to cover a physical gap between the boiler and the flue.

Algar, of Oldham, Gtr Manchester, was again referred to the HSE, who launched legal proceedings against him.

David Thomas, prosecuting on behalf of the Health and Safety Executive, said: “Mr Algar has never been registered and despite telling the HSE that he was now retired he has deliberately and fraudulently held himself out as a Gas Safe registered engineer.” Judge Mark Savill said: “It’s by good fortune nobody died.

“You are someone who thinks the rules don’t apply to them. Your work was slapdash,shoddy and committed in the home a child was living in.

“Your selfish criminality exposed people to risk.

“You are thoroughly dishonest and your dishonesty has affected people for years.”

Son confronts salesman who conned £6k out of his 81-year-old mum with dementia